Accurate potential energy curve of the LiH+ molecule calculated with explicitly correlated Gaussian functions

Abstract

Very accurate calculations of the ground-state potential energy curve (PEC) of the LiH(+) ion performed with all-electron explicitly correlated Gaussian functions with shifted centers are presented. The variational method is employed. The calculations involve optimization of nonlinear exponential parameters of the Gaussians performed with the aid of the analytical first derivatives of the energy determined with respect to the parameters. The diagonal adiabatic correction is also calculated for each PEC point. The PEC is then used to calculate the vibrational energies of the system. In that calculation, the non-adiabatic effects are accounted for by using an effective vibrational mass obtained by the minimization of the difference between the vibrational energies obtained from the calculations where the Born-Oppenheimer approximation was not assumed and the results of the present calculations.

Correlated Gaussian approach to anisotropic resonantly interacting few-body systems

“…The Correlated Gaussian Method is a variational method, which has been used to solve quantum-mechanical few-body problems in molecular, atomic and nuclear physics [31][32][33][34][35]. The method has attained its popularity from the ease of calculating matrix elements in a Gaussian basis [36,37].…”